The present invention relates to a cutting tool insert comprising a substrate and at least one ceramic sintered body preferably of polycrystalline diamond, PCD, or cubic boron nitride, cBN, bonded to the substrate with high strength and rigidity, and a method of manufacturing the same.
Cutting tool inserts for metal cutting purposes with edges of cBN, or a cBN-based material (hereinafter only referred to as “cBN”), or PCD are generally of polygonal shape provided with a PCD or cBN tip in a recess in at least one of its corners. The tips generally are of two different types. In the first type the whole tip is of cBN or PCD or a mixture of these. In the second type the tip is of cBN and/or PCD sintered onto a cemented carbide support. These tips are then brazed onto a regular cemented carbide insert and ground to the finished size. The tips are generally triangular but also more complicated shapes are known such as disclosed in WO 2004/105983. However, because of the high hardness of the PCD or cBN-materials the grinding operation should be restricted to a minimum. In addition, the geometry of the insert can make it very difficult to access some surfaces of the tip with a grinding wheel.